Amy returns from maternity leave. Jake and Rosa work a difficult case.

Captain Holt and Amy manage an understaffed precinct. Jake and Charles investigate.

When the FBI takes over a high-profile case, Jake keeps digging. Amy and Rosa negotiate with O'Sullivan and the police union.

Amid planning for a vow renewal ceremony, Holt makes a big announcement — one that he asks Jake not to share with Amy. Plus, Cheddar wears a bow tie!